1. Field of the Invention
The present invention relates to a light-emitting device, in particular to the light-emitting device having a light-emitting diode (LED) or the like.
2. Description of the Related Art
A light-emitting element such as the light-emitting diode or the like is manufactured normally as follows: an n-type semiconductor layer, a light-emitting layer, and a p-type semiconductor layer are grown on a growth substrate, and then an n-electrode and a p-electrode are formed on the n-type semiconductor layer and the p-type semiconductor layer respectively for applying a voltage thereto. Further, the light-emitting element is fixed on a first substrate on which wirings or the like are formed, and then is sealed on the light extraction surface with resin or the like to form the light-emitting device.
In recent years, there is achieving high luminance of the light-emitting element, high luminance elements are marketed and readily available. In addition to achieving high luminance of the light-emitting element, there are demands for the use of indicators or the like or low luminous intensity products.
Japanese Patent Application Laid-Open No. 2002-111073 discloses a light-emitting diode in which the adjusting of color tone is achieved by adding phosphor particles and pigment particles to a resin material for sealing and protecting the light-emitting element chip. Japanese Patent Application Laid-Open No. 2004-128424 discloses a white light-emitting device in which the adjusting of luminance variance is achieved by adding a black-based pigment as a light-extinction material mixed with phosphor particles to a covering member.
According to the light-emitting device disclosed in Japanese Patent Application Laid-Open No. 2004-128424, it has been difficult to control the luminous intensity of device by adjusting the amount of black-based pigments to be mixed to the covering member with phosphor particles, because change in the luminous intensity with respect to the change of the mixture ratio of pigments is so large. Further, there are difficulties to obtain a light emission surface for uniformed luminance and chromaticity. Further, since the covering member becomes black as a whole, design characteristic (light emission surface color) becomes differed in comparison with the light-emitting device without the black pigment.